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Research paper : A rationalization guideline for the utilization of energy and resources considering total manufacturing processes (H. Kita et al.)−205 Synthesiology - English edition Vol.1 No.3 (2009) furnaces that will increase production volume per unit time, but optimization of total system must be conducted while considering facilities investment and production volume.Exergy, which was born from heat engineering, is considered as common thread between effective energy and materials, but it is not sufficiently systematized from physical perspective such as dealing with interface and surface as mentioned above. This is future issue in increasing the accuracy of the index.③Design and othersAs mentioned earlier, since ceramics is extremely stable in molten aluminum, it does not have to be solid body. Not only does hollow structure design and process reduce amount of material used, but also will decrease heat stress by thinning and will shorten sintering time, and these are extremely useful for improving efficiency.On the other hand, ceramics is not suitable for recycling. Both company and consumer must become conscious of using ceramics members as long as possible because they were manufactured using great amount of exergy input. In technological development, considering the characteristics of ceramics, development of design and process that allows exchange of damaged parts and reparable structure is necessary.3.5.3 Innovation in casting systemLooking at the overall casting operation, there are two operations in which solid is melted, and heat is radiated considerably in delivery process (Figure 4). Exergy necessary to melt solid was calculated to be about 19000 GJ (4300 per ton). To decrease this, development of molten metal delivery system, where molten aluminum melted outside is placed in insulating container, delivered directly into plant in molten state, temperature adjusted in holding furnace, and then formed, is being done by major automobile companies. It is expected that efficiency will increase since one process of melting-solidification is reduced. However, currently there are problems such as insufficient insulation of the transporting container that demands external heater during delivery process, as well as high fuel consumption in transportation process because the container itself is heavy. Delivery of molten metal is highly efficient system in principle and diffusion is expected, but development of lightweight container with excellent insulation is the key.The centralized melting furnace, which will become the center of the above delivery system, will be on continuous run once aluminum is melted in the furnace to maintain the molten state. Considering that it is necessary to put in energy regardless of amount, the ultimate system will be to deliver the metal into the plant as solid, and to melt only necessary amount to produce the product. There are several issues before this system can be realized, such as heating source that enables instant melting, excellent insulation which is component of system, large ceramic tube and container that the molten metal will not adhere, engine design that allows easy disassembly, and establishment of recovery system of disposed engine in the society. It is necessary to solve individual issues while considering the overall exergy balance.(51)−Ex: ExergyInput Ex□Surface derived Ex□Chemical ExEx of raw material□Surface and interface derived Ex □Arrangement ExEx of product□Ex for heating furnace material etc.□Activated ExLeast amount of input Ex necessary□Excess Ex★Switch to low exergy material★Design (hollow structure)★Catalyst★Heat recovery★Reduced time by thinning★Improved yield and payloadReference material Ex = 00Exergy levelFig. 11 Rationalization of ceramics process.

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